There is a continuing need for materials and chemistries that can form polymers, including crosslinked polymers, rapidly under ambient or mild conditions, particularly in the presence of oxygen.
Various methods for adhesively bonding low surface energy substrates such as polyethylene, polypropylene, and tetrafluoroethylene, as well as higher energy substrates have been developed. One approach involves the use of acrylic bonding compositions that include acrylic monomer, an organoborane-amine complex, and a decomplexing agent, i.e., a compound that decomplexes the amine from the organoborane, which then initiates polymerization of the acrylic monomer.
Due to their unstable nature, such acrylic bonding compositions are typically supplied as two-part systems that are to be mixed immediately prior to use. The two-parts consist of a part A composition (often called Part A composition) that contains an organoborane-amine complex in a reactive diluent, and a second part (often called Part B) that contains a polymerizable monomers and polymer. Various reactive diluents have been described that can be added to bonding compositions, including 1,4-dioxo-2-butene-functional compounds as reported in U.S. Pat. No. 6,252,023 (Moren) and aziridine-functional compounds as reported in U.S. Pat. No. 5,935,711 (Pocius et al.). Vinyl aromatic compounds of the type reported in PCT Publication WO 01/68783 (Moren) have also been disclosed. These reactive diluents all have shortcomings, including instability in the presence of the organoborane-amine complex and/or toxicity.